Mahogany, Southern | Eucalyptus botryoides

Southern mahogany is a native Australian hardwood popularly used for indoor and outdoor applications as well as furniture and cabinetry.

Other Names: Bangalay (NSW), Gippsland Mahogany (Vic), Woollybutt, Swamp Mahogany or Mahogany Gum.

Overview

Southern mahogany is a large, fast-growing species indigenous to coastal south eastern Australia, from Bairnsdale in Victoria to north of Newcastle in NSW. It is closely related to Sydney blue gum and is valued for its rapid growth, tolerance of frost and striking red wood.

An excellent timber tree, it has deep pink to red-brown heartwood with distinctively paler sapwood. The timber is hard, strong and dense with a medium, even texture and interlocking grain. It is durable and lyctid borers rarely attack the sapwood.

Southern mahogany seasons readily. It turns, machines, and glues well but can blunt knives and saws more quickly than other eucalypts. It is prone to severe growth stresses when young and should be quarter sawn to reduce damage. It can be difficult to dry and air-drying in protected stacks can reduce its susceptibility to end splitting and collapse.

The timber is used in cabinetry, furniture, flooring, decking, and veneer applications as well as general construction, poles and firewood. Historically it was used in heavy construction for sleepers and posts. 

 

Properties

Shrinkage

Very Low Low Medium High Very High
Tangential:          
9.8
Radial: > 5
Unit Movement: 0.37 %

Strength Group

Very High High Reasonably High Medium High Medium Reasonably Low Low Very Low
Unseasoned:S1S2S3S4S5S6S7
Seasoned:SD1SD2SD3SD4SD5SD6SD7SD8

Stress Grade

Structural
No. 1
Structural
No. 2
Structural
No. 3
Structural
No. 4
Structural
No. 5
Unseasoned: F27 F17 F14 F11 F8
Seasoned: F27 F22 F17 F14 F11

Density per Standard

Unseasoned: 1180 kg/m3
Seasoned: 900 kg/m3

Joint Group

Very High High Reasonably High Medium Low Very Low
Unseasoned:J1J2J3J4J5J6
Seasoned:JD1JD2JD3JD4JD5JD6

Colour

  White, yellow, pale straw to light brown Pink to pink brown Light to dark red Brown, chocolate, mottled or streaky
   

Mechanical Properties

Modulus of Rupture - Unseasoned: 84
Modulus of Rupture - Seasoned: 130
Modulus of Elasticity - Unseasoned: 15
Modulus of Elasticity - Seasoned: 18
Maximum Crushing Strength - Unseasoned: 46
Maximum Crushing Strength - Seasoned: 77
Impact - Unseasoned: 18
Impact - Seasoned: 18
Toughness - Unseasoned: Medium - 15 - 25 Nm
Toughness - Seasoned: Medium - 15 - 25 Nm
Hardness - Unseasoned: 7.0
Hardness - Seasoned: 9.0

Durability

Low Moderate Reasonably High High
(0 - 5 yrs) (5 - 15 yrs) (15 - 25 yrs) (more than 25 yrs)
In-Ground:
(0 - 7 yrs) (7 - 15 yrs) (15 - 40 yrs) (More than 40 yrs)
Above ground:
(0 - 20 yrs, usually < 5) (21 - 40 yrs) (41 - 64 yrs) (More than 60 yrs)
Marine Borer Resistance:
Lyctid Borer Susceptibility: Not Susceptible
Termite Resistance: Resistant

Fire Properties

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
EFH Ignitibility:
0 1 2 3 4 5 6 7 8 9 10
EFH Spread-of-Flame Index:
EFH Smoke-Developed Index:
1 - non-combustible 2 - reasonably non-combustible 3 - slightly combustible 4 - combustible
Fire Properties Group
Number:
Group Number - Other: 3 if used on MDF or particleboard ≥12mm; veneer thickness 0.6-0.85mm
Average Specific Extinction Area: <250
Bushfire Resistance: BAL 12.5 and 19 – All AS3959 required applications

Description

Botanical Name: Eucalyptus botryoides
Preferred Common Name: Mahogany, Southern
Other Names: Bangalay (NSW), Gippsland Mahogany (Vic), Woollybutt, Swamp Mahogany or Mahogany Gum.
Species Type: Hardwood

Appearance

Southern mahogany features deep pink to red-brown heartwood with a distinctively paler sapwood. The timber is hard, strong and dense with a medium, even texture and interlocking grain. 

 

Common Applications

The timber is used in cabinetry, furniture, flooring, decking and veneer applications, as well as general construction, poles and firewood.

 

Common Form

Sawn

Workability

Southern mahogany seasons readily. It turns, machines and glues well but can blunt knives and saws more quickly than other eucalypts. It is prone to severe growth stresses when young and should be quarter sawn to reduce damage. It can be difficult to dry.

 

Origin of Timber

NSW, VIC

Readily Available

NSW

Availability - Further Information

Southern mahogany is relatively common on the south coast of NSW.

Source of Timber

Native Forest

Applications

  • Architectural Roof Trusses

    Architectural timber roof trusses create strong visual impact. Often used as part of ‘cathedral ceiling’ systems, timber can be specified light or heavy to suit the chosen theme and style. On finish, they can be left natural or may be oiled, stained, painted or highly decorated. Choice is limited only by individual style and design preferences.

  • Decking

    Timber decking creates spaces that are functional, practical and aesthetically pleasing. With the right design and care a timber deck will make a valuable addition to any home or business, creating an outdoor living space that will be enjoyed for years to come.

  • Flooring

    Whether for structural or finished flooring applications, timber offers durability, versatility and adaptability. The warmth, strength and natural beauty of timber flooring has proved enduringly popular in a wide variety of interior settings.

  • Structural Timber Poles

    Timber poles are utilised in structural construction to provide support for gravity loads and resistance against lateral forces. Not only serving a structural function, timber poles provide many aesthetic benefits, with their use in construction often complementing architectural designs aimed at harmonisation with the natural environment.

  • Timber Joinery Products

    Timber joinery products offer a classic, unique and stylish touch to any interior design.

  • Timber Portal Frames

    For buildings that require large spans and column free interiors, timber portal frames provide one of the most aesthetically pleasing solutions. Utilising modern engineering technology, portal frame design transforms timber into a highly effective, efficient and economical structural product. This application guide provides a comprehensive overview of the process of using timber in the specification, fabrication and erection of portal frame structures.

Case Studies

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